1. Field of the Invention
The present invention relates to a vehicle seat mounted side air bag restraint system.
2. Background Art
Vehicle seat air bag restraint systems are used to protect vehicle occupants in the event of a side impact. To be effective, air bag restraint systems must deploy rapidly. Vehicle seats generally include a rigid frame to which foam pads are secured. The seat is enclosed within a cover made of vinyl, cloth or leather. Air bag modules are secured to the seat frame and generally include a housing, an air bag and an inflator system.
The elasticity of covering materials and urethane foam padding present a problem for air bag deployment. As the air bag deploys, it must be channeled so that the air bag deploys through an air bag tear seam in the seat cover material. The elasticity of the seat cover material allows the air bag to expand and cause the seat cover material to bulge. This may increase air bag deployment time and result in variation in air bag deployment location. The resiliency and tendency of the foam material to deform or fragment is another problem that must be solved.
One attempt to solve the above problems is disclosed in U.S. Pat. No. 6,045,151 to Wu that employs a force concentrator that at least partially surrounds the folded air bag and concentrates or directs the force of the inflating air bag to the designed deployment seam. The force concentrator avoids application of air bag deployment load on the trim cover material to reduce the influence of the trim cover as a design factor for air bag deployment. The force concentrator is an inelastic structure that surrounds or at least partially surrounds the air bag of an air bag module. This patent requires two panels to form the force concentrator. The use of two panels complicates and assembly and may require that multiple pieces be joined together by seams. The Wu patent also discloses that a single panel may work on only one side of the deployment seam, but states that it must be verified that the addition of the concentrator does not induce trim cover failure elsewhere.
In developing alternative designs to solve the problems associated with the Wu patent, other problems are presented that relate to assembling the air bag module to the seat with the force concentrator. It is difficult to assemble the module to the seat frame, the concentrator and the seat cover. The cost of the component parts including the cost of the concentrator fabric should be minimized and the labor required to perform the assembly operation must also be minimized. In addition, the speed of deployment and deployment location must be controlled and predictable for product specification and quality standards certification.
Applicant's invention is directed to solving the above problem as summarized below.